Automatic emulsion control

ABSTRACT

Apparatus for controlling the basic sediment and water content of an oil field produced fluid by continually controlling the rate of injection of treatment chemical to and the rate of heat treatment of said fluid in response to the BS&amp;W level of said fluid.

United States Patent 1191 Underwood Mar. 12, 1974 [54] AUTOMATIC EMULSION CONTROL 3,005,554 10/1961 Kuntz 210/96 l6 l2 [75] Inventor: Claud W. Underwood, Dallas, Tex. 3'l73 H964 Kumz 210,96 X

[73] Assignee: Sun Oil Company (Delaware),

Dallas, Tex. Primary Examiner-John Adee Attorney, Agent, or FirmG. L. Church; D. R. John [22] Filed: Aug. 31, 1972 Son Esq [21] Appl. No.: 285,299

[52] US. Cl 210/96, 210/59, 2lO/7l, [57] ABSTRACT 210/187 [51] Int. Cl BOld 21/01 A aratu 'for controlling the basic sediment and Field of Search Q, water content of an oil field produced fluid by contin- 210/ ually controlling the rate of injection of treatment chemical to and the rate of heat treatment of said fluid [56] References Cit d in response to the BS&W level of said fluid.

UNITED STATES PATENTS 1,943,367 1/1934 Champion 210/71 2 Claims, 1 Drawing Figure .5 6 (g 7 V a (0-1-1 t \VJ'L] 7 G45 4/:

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)1 2/ m a gnu/mu mun'r/a/v J TR P Q PATENTEU "AR 1 2 I974 AUTOMATIC EMULSION CONTROL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the control of the rate of chemical injection and heat treatment of a fluid in re sponse to a measured property of the fluid which represents the treated condition. More particularly the invention relates to apparatus for controlling BS&W (basic sediment and water) content of an oil field produced fluid by controlling the rate of injection of a chemical responsive to the BS&W content and by controlling the rate of heat treatment also responsive to BS&W content.

2. Description of the Prior Art Crude oil commonly is treated to remove BS&W by pumping the oil to a treating tank in which it is mixed with treating chemical. The injection rate is usually set to inject the greatest amount of chemical required for emulsion control with a usual additional safety factor. This method, with its tendency to overtreat, is often inefficient since excessive chemical is used and, in fact, oil is given away since a BS&W content lower than than contracted for in prospective sales usually results. Often a storage tank is filled with non-marketable oil which requires circulation of the tank contents through heating means, additional chemical requirements and the consequent loss of time all of whichincrease the cost of getting the oil into the market pipeline.

SUMMARY OF THE INVENTION Apparatus has now been found which minimizes chemicalconsumption and controls heat treatment of oil field produced fluids which comprises:

a. means for storing said fluid b. means for detecting the BS&W content of (a) c. heat treatment means (1. chemical injection means e. logic circuit or computer means with the capability to translate the BS&W content of a tank as detected by (b) above into a responsive circulation of the contents of said tank through either (c), (d) or both in order to reduce said BS&W content of the fluid in said tank.

The advantages of such a system are decreased chemical cost due to continual monitoring of BS&W levels and more accurate treatment rates, more efficient use of heat treatment due to said monitoring and control and prevention of buildup of unm'arketable oil in a tank which otherwise necessitates closing off and time consuming treatment of the oil in said tank.

The means for detecting BS&W content may be any of the known devices such as a capacitance probe as disclosed in US. Pat. No. 3,648,165.

A better understanding of the invention as well as a full appreciation of the advantages will be had upon study of the schematic drawing, illustrating the preferred embodiment which follows:

DESCRIPTION OF THE DRAWING AND THE PREFERRED EMBODIMENT Oil field produced fluids, for example crude oil, are pumped to storage facilities such as Tanks 1, 2 and 3 viainlet lines 5, 6 and 7 respectively. Any number of tanks may be included in the system, but three are shown here for the sake of simplicity.

Since all tanks have the same pipe, valve and control cable configuration, the Tank 1 system only will be described. However, it must be remembered that the Tank 1 system acts in parallel to the other tanks in the process.

The oil in Tank 1 contains a given BS&W level which is sensed by a capacitance probe, 8. This value is transmitted as a signal via cable 9 to the computer unit 10 which contains a series of function blocks. The first function block, 11, compares the BS&W value, as translated from the signal, to an acceptable limit, in this case 1.9 percent. If the BS&W of the tank is below this desired level, no action is necessary and function block 12 maintains all systems in an OFF condition. If the BS&W of the fluid in Tank 1 is greater than 1.9 percent, function block 13 is activated. This block controls solenoid valves 14 and 15 on Tank 1 and they are opened. Simultaneously, circulating pump 17, connected by control cable 16 to circuit 13 is started and the other tanks in the system are blocked off in an arrangement like that used to open Tank 1. The oil from Tank 1 is now free to circulate via valve 14, line 18 and pump 17 through the heater treater unit in which the emulsion is broken by heat. The treated oil then is withdrawn via line '20 and returned to the Tank through open valve 15.

If the BS&W is at such a level that heat treatment alone will not suffice, chemical injection is needed. Function block 21 compares the Tank BS&W to an arbitrary figure, here 2.2 percent which has been predetermined to be a level which requires chemical injection. If the Tank BS&W is less than this given level, function block 22 is activated, maintaining the chemical injection loop in an OFF condition. If the Tank BS&W is greater than the acceptable level, function block 23 is activated which regulates the chemical injection pump 25 via control cable 24. This pump withdraws a suitable emulsion-breaking chemical from tank 26 and injects it into line 18 on the suction side of pump 17 allowing pump 17 to mix the chemical into the oil stream prior to charging the entire mixture to heater-treater l9.

Pump 25 is shown here as gas driven via feed line 27 and valve 28, but this pump can also be electric or steam driven. Computer unit 10 also includes a set of manual tank solenoid override switches 29, so that manual operation can supplant automatic operation in case of a system problem.

As the oil is being circulated through the system, capacitance probe 8 is continually measuring the BS&W level and chemical and heat treatment will be controlled according to the values obtained by this probe. This leads to economic use of chemical and constant control of BS&W in oil field produced fluids contained in the tanks. 1

I claim as my invention: 1. Apparatus for controlling the basic sediment and water content of a fluid comprising:

a. means for monitoring basic sediment andwater content of said fluid and transmitting a first electronic signal proportional to said basic sediment and water content, b. means for heating said fluid, c. means for injecting treating chemical into said fluid, d. means for receiving said first electronic signal,

comparing said first electronic signal to a first stanmeans for receiving said first electronic signal,

comparing said first electronic signal to a second standard signal, proportional to a basic sediment and water content essentially higher than said acceptable basic sediment and water content, and transmitting a third electronic signal proportional to the difference between said first electronic signal and said second standard signal,

f. means for receiving said second electronic signal and controlling a proportional response in (b), and

g. means for receiving said third electronic signal and controlling a proportional response in 2. Apparatus of claim 1 wherein said means for'heating said fluid is a vessel through which said fluid is circulated. 

1. Apparatus for controlling the basic sediment and water content of a fluid comprising: a. means for monitoring basic sediment and water content of said fluid and transmitting a first electronic signal proportional to said basic sediment and water content, b. means for heating said fluid, c. means for injecting treating chemical into said fluid, d. means for receiving said first electronic signal, comparing said first electronic signal to a first standard signal, proportional to an acceptable basic sediment and water content, and transmitting a second electronic signal proportional to the difference between said first electronic signal and said first standard signal. e. means for receiving said first electronic signal, comparing said first electronic signal to a second standard signal, proportional to a basic sediment and water content essentially higher than said acceptable basic sediment and water content, and transmitting a third electronic signal proportional to the difference between said first electronic signal and said second standard signal, f. means for receiving said second electronic signal and controlling a proportional response in (b), and g. means for receiving said third electronic signal and controlling a proportional response in (c).
 2. Apparatus of claim 1 wherein said means for heating said fluid is a vessel through whiCh said fluid is circulated. 